Instead of picturing the Underworld star, USA Today used a photo of Kate Middleton, aka the Duchess of Cambridge and actual royalty.

Beckinsale poked fun at the mistake on her Instagram and shared a screen shot of the mishap with her followers.

Kate Beckinsale. Picture: LISA O'CONNOR WSource:AFP

Kate Middleton. Picture: Ian RutherfordSource:Getty Images

“Back to resume my royal duties. William says hi,” she wrote in the photo’s caption.

While Beckinsale’s post attracted a humorous response from her celebrity followers Sarah Hyland and Rose McGowan, it also prompted USA Today to issue a grovelling apology.

“First and foremost, we’re glad to hear you’re feeling much better. We apologise for the image associated with this story. It appears our system pulled the first image in the photo gallery at the bottom of the story, instead of the image of you we put in the story,” the publication wrote underneath Beckinsale’s post.

“It just so happens the lead photo in the gallery is of Duchess Kate. We regret the error and are working to make sure this does not happen again.”

Over the weekend Beckinsale revealed on Instagram she had been hospitalised after suffering a ruptured ovarian cyst.

“Turns out a ruptured ovarian cyst really hurts and morphine makes me cry. So thankful to everyone who looked after me #wobbly,” she captioned her post.